This invention is generally directed to developer compositions, and more specifically, the present invention relates to developer compositions with coated carrier components, or coated carrier particles that can be prepared by, for example, dry powder processes. More specifically, the present invention relates to compositions, especially carrier compositions comprised of a core and thereover terpolymers of (1) styrene/alkyl methacrylate/monoalkyl hydrogen aminoalkyl methacrylate, or (2) styrene/dialkyl aminoalkyl methacrylate.
In embodiments of the present invention, the carrier particles can be comprised of a core with a coating thereover of terpolymers of styrene, n-butyl methacrylate and dimethylaminoethyl methacrylate; terpolymers with styrene/n-butyl methacrylate/dialkyl aminoethyl methacrylate where dialkyl is dimethyl, diethyl, diisopropyl, di-n-butyl, di-n-hexyl, and the like, terpolymers 1s with styrene/n-butyl methacrylate/monoalkyl hydrogen aminoethyl methacrylate where monoalkyl is t-butyl, like t-butylaminoethyl methacrylate, and the like. The carrier may include the polymer coating thereover in admixture with other suitable polymers, and more specifically, with a second polymer, such as a fluoropolymer, polymethylmethacrylate, poly(urethane), especially a crosslinked polyurethane, such as a poly(urethane)polyester and the like, and moreover, the polymer coating may contain a conductive component, such as carbon black, and which conductive component is preferably dispersed in the copolymer coating. With the conductive component there can be enabled carriers with increased developer triboelectric response at relative humidities of from about 20 to about 90 percent, improved image quality performance, excellent high conductivity ranges of from about 10.sup.-10 to about 10.sup.-7 (ohm-cm).sup.-1, and the like. An important advantage associated with the carriers of the present include a high triboelectrical charge, for example a carrier tribo range of from about a plus (positive charge) 50 to about 150, or to about 95 microcoulombs per gram, and preferably from about a positive 55 to about a positive 90 microcoulombs per gram, and most preferably from a positive about 60 to a positive about 70 microcoulombs per gram. The carrier particles of the present invention can be selected for a number of different xerographic copiers and printers, such as high speed color xerographic copies, printers, digital copiers, and more specifically, wherein colored copies with excellent and substantially no background deposits are achievable in copiers, printers, digital copiers, and the combination of xerographic copiers and digital systems. Developer compositions comprised of the carrier particles illustrated herein and prepared, for example, by a dry coating process are generally useful in electrostatographic or electrophotographic imaging systems, especially xerographic imaging and printing processes, and digital processes. Additionally, the invention developer compositions comprised of substantially conductive carrier particles are useful in imaging methods wherein relatively constant conductivity parameters are desired. Furthermore, in the aforementioned imaging processes the triboelectric charge on the carrier particles can be preselected depending on the polymer composition and dispersant component applied to the carrier core and the type and amount of the conductive component selected.